Drifting-valve for locomotives.



F. SHOEMAKER.

DHIFTING VALVE FOR LOCOMOTIVES.

APPLICATION FILED JULY 30, 1914.

"1,149,960. Patented Aug. 10, 1915.

2 SHEETS-SHEET I.

Fig. 1.

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F. SHOEMAKER.

DRIFTING VALVE FOR LOCOMOTIVES.

APPLICATION FILED JULY 30, 1914.

Patented Aug. 10, 1915.

2 SHEETS-SHEET 2- coLuMmA PLANOGRMII c0.. WASHINGTO D. C.

FRANK SHOEMAKER, (or WATERLOQQIOWA, ASSIGNOR or onE-imnr T CLIFTON n. e noxnv, or WATERLOO, IOWA. 7

narrative-VALVE ron LOCOMOTIVES.

Specification of Letters Patent. at te Au 5.

Application filed Ju1y30, 1914; Serial No. 854,157.

To all whom it may concern specification.

My invention relates to improvements in drifting valves for locomotives, and the object of my improvement is to furnish means for, automatically supplying low pressure steam to the cylinders, when the locomotive is drifting with the main throttle-valve closed, for the purpose of preserving the lubrication of the cylinders in effective condition, cushioning the pistons and preventing the burning out of the superheater units of superheater locomotives. This object I have accomplished by the means which are.

hereinafter described and claimed, and which are illustrated in the' accompanying drawings, in which:

Figure 1 is a vertical central longitudinal section of my improved drifting-valve for locomotives, showing a part of the lever broken away. Fig. 2 is a like section of said device, showing the movable parts thereof in different positions from those shown in Fig. 1. Fig. 3 is a diagram showing the means of communication between the parts of said drifting-valve, steam-domeand drypipe, and the steam-chest of the locomotive.

Similar numerals of reference denote corresponding parts throughout the several views. 7

I am aware that drifting-valves have been invented to be employed in supplying steam at a low pressure to the cylinders of a loco-- 'motive at times when full boiler steam pres sure has been cut off by means of the throttle-valve. This low pressure of steam is required in the cylindersat such times in order to keep the cylinders warm, prevent the pumping of cool air thereinto withthe resultant'congealing of the lubricating oil'and consequent undue scoring and. wear of the cylinder by the piston-head, and furthermore, to provide steam cushions between each piston-head and the cylinder-heads.

In practice, the boiler pressure of the 10- comotive ismaintained at a certain maximum while in use, but notwithstanding this, fluctuations in thepressure of the steam are certain to occur, and therefore it is abso- -the"central orifice intheadjacent cylinderlutelynecessary that a drifting-valve should be operateduhder all such variations of boiler pressure to maintainat all times approximately the same low steam pressure in the cylinders. My improved drifting-valve is designed to successfully effect this obj ect'. Figs. 1 and 2show a' casting in which'is supplied with one closed and one centrally orificed head. The differential cylinder contains interior hollows 2 and'8 of different diameters which are adapted to'receive the differential heads 4: and 5, respectively of the differential piston, such heads being spaced and connected by means of a-central rod 3. The smaller piston-head 4 has a piston-rod 20 extending through the adjacent orificed cylinder-head, and provided on its outer extremity with a rectangular boxing 21' containing a slide 22 in which .a pintle 23. is pivotally mounted. The other cylinder 11 contains a reciprocatory piston-head 16 provided with a piston-rod 17 movable through head, and provided on its extremity with a like rectangular boxing 24 containing a slide 25 in'which a pintle 26 is likewisepivotally mounted. The numeral 18 denotes a fixed arm on the orificed cylinder head of the cylinderl, provided with a forked bearing having a pintle 31 on which one extremity of a lever 19 is pivotally mounted. This lever is madeup of two like spaced members in whichv the ends of the pintles 23 and 26 are mounted on'opposite sides of the bodies 21 and 24. The other extremity of said lever formed a differential cylinderl and a par- 'allel' cylinder 11 of the ordinary type each is formed into ahandlefor manual use as 4 hereinafter to be described. 2 The numeral 27 denotes a fixed arm projecting from the ori- 'ficed head of the cylinder 11 and to whose outer end a swinging stop 28 is pivoted on a pintle 32. Said stop has its other end bifurcated with the forks connected by the bar 29. In the position shown in said Fig. 1, the stop' 28 has been swung outwardly to engage and hold the lever 19 in its extended position. this position, the rod 29 prevents the stop 28 from swinging over any farther. Fig.2, said stop is shown as moved over lever. I a A The numeral 30 denotes an inlet-port in out of engagement with said the cylinder 1 in communication with that part of its inner chamber 2 which forms the chamber 33 and the outer atmosphere.

interspace of two piston-headse ands. This port is placed in communication with the steainunder boiler "pressure inthe dome of the locomotive by means of a conduit 38 I controlled by a shut-01f cock. 3? 131161 6111.

Said cylinder 1 contains'an annular passage Or channel ooncentrlctherewith and separated from its interior hollow by means of a sleeve 36 fitted into the cylinder to-cover and form the inner wall of the channel. This sleeve orcy'lindrical ring 351s provided with a plurality of like orifices or ports 6 arranged concentrically around it in a single row, spaced from-the ad acent cylinder-head, and lying within the path of travelof the larger piston-head 5, so as to be more or less coveredthereby variably as said piston is -moved. Said cylinder has. an

outlet port 7 in communication with the channel 15'and also in communication with the dry-pipei by means of a conduit 34. V

The chambers Sand 33, located respectively between the left hand ends ofthe pistons 4c and 16 and the adjacent cylinder heads, are

' placed in communication by means of a pasber 80f the cylinder 1 to the chamber 12 of the cylinder 11, and is adapted to transmitlow pressure steam from the-onetothe other. The cylinder 11 has an outlet-port 13 in communication. between the chamber 12 and the steam-pipe part by means of conduit 39. The drifting-valve is mounted on a bracket 42 in the cab. of the locomotive.

Operation: Said Fig. 1 shows the positionsof the moving parts of the device when the lever 19 is held at its extreme left hand position by meansof the stop 28 to cut off communication between the inlet-port 30 and the outlet ports 6 1 The conduit 34:

which leadsfrom the ports 6 and the channel 15 by way of the port 7 to the dry-pipe 35' communicates with said dry-pipe; below the shut-off valve of the throttle. It will be seen that when steam is throttled in said dry-pipe, andthestop 28 has been thrown over out of engagement with the lever 19, that the steam, at fullboiler pressure, contained in the chamber 2, .will operate to push the piston-head 5 to the right on account of the difi'erence in diameters of the two heads 4: and 5. This will cause the piston to travel to the right untilithe ports-.6 are suficiently uncovered to allow opening enough to maintain the specified. low pressure in the cylinders. Steam passing at full boiler pressure through the partially or wholly opened ports 6. into thechannel 15, port 7, conduit 34;, and dry pipe 85, will become expanded in said channels so as to enter the locomotive cyllnders at a low relative pressure.

*Theconduit '39 conducts a portion of this low pressure steam from the dry-pipe part 10 back to the interspaces 12 and 8 of the two cylinders 11 and 1, respectively. This low pressure steam not only pushes the piston 16 to the left, but also acts upon the piston head -5 against the opposite full boiler pressure thereon. The areas of the two pistons 5 and 16 have certain relative proportions'respectively to the small piston e de termined suitably to maintain by means of the low steam pressure thereon an approxi-- mately unvarymg resistance to the full steam pressure upon said head 5. This rela tion has a ratio which is based upon the boiler pressure ordinarily used as a maximum orrworking pressure on the locomotive,andthe length of the power arm hasa V relation to the length of the weight arm of the lever 19 such as will suitably magnify the tractive efiort or pull exercised by said lever upon the differential piston in the cylinder 1 and such as will sufliciently act upon the larger -pistonhead 5 in' addition to the low steam pressure thereon: Thenet result is to equalize the action of said differential piston so that under ordinary working pressures of steam in the boiler,aa supply of low pressure steam will be furnished the cylinders at low pressures of very slight variation. My device is thus operative to automatically vary the low steam pressure in the cylinders. within .very slight "limits and relatively proportional to the varying boiler pressures, and will thus work effectually under all conditions of use. 7

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is: I Y

1. A drifting valve for a locomotive, comprising a valve-chamber provided with both inletand outletport-s, movable elements in saidchamber, and mechanism without said chamber linked to said elements operatively, said interconnected elements and mechanism being adapted .to control the outlet-port of said chamber to automatically relate, the

pressure of steam delivered by the outletport to the pressure of steam received by the inlet-port to maintain the steam delivered by said outlet-port to the cylinder of the locomotive suficiently above atmospheric pressure as to provide cushioningemeans therein without exercising a'driving effect on the 10- comotive. v r

, 2. In combination, a dilferential cylinder, a difierential piston therein, said cylinder having an inlet-port in communication between the interspace of: the piston-heads and a supply of steam under boiler pressure, and having an outlet-port in the path of travel of the large piston-head, a conduit between said outlet-port and a steam chest, a second cylinder, a piston therein, the said differential plston having a rod pro ecting from its between the lengths of the weight arm and power arm of the lever, said cylinders having means of communication between the i11 terspace of the large piston-head and the adjacent cylinder-head of the differential cylinder and the interspace of the secondmentioned cylinder between its piston and its cylinder-head on the same side as said othercylinder-head, and said conduit to the steam chest, the said cylinders having means of communication between their other adjacent ends and the atmosphere.

3. In combination,a differential cylinder, a differential piston therein, said cylinder having an inlet-port in communicationbetween the interspace of the piston-heads and a supply of steam under boiler pressure, and having an outlet-port in the path of travel of the large piston-head, a conduit between said outlet-port and a steam chest, a second cylinder, a piston therein, the said differential piston having a rod projecting from its small head vand the other piston having a rod projecting in the same direction as, the

first-mentioned rod, a leverhaving a fulcrum at one extremity and swiveled to both said rodssuitably ,portion between the lengths of the weight arm and power arm of the lever, and mean for removably holding said lever in a certain position, said cylinders having means of communication between the large pistonhead and the adjacent cylinder-head of the difierential cylinder and the second-mentioned cylinder between its piston and its cylinder-head on the same side as said other cylinder-head and said conduit to the steam chest, the said cylinders having means of to mainta'in a desired procommunication between their other adjacent 7 ends and the atmosphere.

Signed at Waterloo, Iowa.

FRANK SHOEMAKER. Witnesses:

PEARL STANTON,

GEO. G. KENNEDY.

Copies of this patent may be'obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

